Sine plate assembly



March 18, 1969 scH 3,432,934

SINE PLATE ASSEMBLY Filed Aug. 30. 1966 INVENTOR. HERMANN SC HMI DTATTORN EYS 3,432,934 SINE PLATE ASSEMBLY Hermann Schmidt, 237 BurnhamSt., East Hartford, Conn. 06108 Filed Aug. 30, 1966, Ser. No. 576,092US. Cl. 33 174 Int. Cl. G01b 5/20 5 Claims ABSTRACT OF THE DISCLOSUREThis invention generally relates to precision tools and particularlyconcerns sine plates and the like usable, for example, in accuratelyholding a workpiece at a selected angle.

A primary object of the invention is to provide an improved sine plateparticularly suited for quick and easy manufacture and assembly andwhich will provide long, reliable service.

Another object of the invention is to provide an improved sine platecapable of accurately setting sines of small angles at minuteincrements.

A further object of the invention is to provide a sine plate of theabove described type :having an improved clamp for retaining the platesof the assembly in a desired angular relation and which is of durable,compact and economical construction particularly suited for quickattachment and release.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereafter set forth, and the scope ofthe application of which will be indicated in the appended claims.

In the drawing:

FIG. 1 is a side elevational view, partly broken away and partlyexploded, showing a sine plate assembly constructed in accordance withthe present invention; and

FIG. 2 is a front elevational view of the assembly of FIG. 1, explodedin part, partly broken away and partly in section.

Referring now to the drawing in detail, a preferred embodiment of a sineplate assembly of this invention is shown generally comprising a basemember or plate upon which a top member or plate 12 is pivotally connected adjacent its rear end 14, the top plate 12 being shown as havinga plurality of openings 16. Plates 10 and 12 are preferably formed ofhardened ground steel each having an upper face 18 and 20 with fineprecision finished surfaces. The base plate 10 thus provides a flatmaster surface from which vertical measurements are taken in nitedStates Patent 0 accordance with conventional techniques by means of aprecision gage block 21, or combination of gage blocks, and the topplate 12 provides an accurately fiat work support surface.

As best seen in FIG. 2, a front roll 22 and a pivot shaft 24 are spacedapart a preselected standard distance and secured in position, e.g., byscrews, not shown, across a lower face 26 of the top plate 12 adjacentits front end 28 and rear end 14 respectively.

In accordance with one feature of the present invention, thelongitudinal axes or center lines of the pivot shaft 24 and the frontroll 22 are readily and precisely positioned parallel to one another ina common plane parallel to the finished upper faces 18 and 20 of plates10 and 12 when the front roll 22 is in engagement with the base plate10. This is accomplished by means of a pair of end bushings 32, 34precisely located in a lateral recess 36 extending inwardly fromopposite sides 38, 40 of the base plate 10-. Bushings 32, 34 areaccurately formed cylinders having equal outside diameters greater thanthat of the pivot shaft 24, and the rear corners of the lower face 26 ofthe top plate '12 are shown cut away at 42 and 44 to provide sufiicientclearance for the enlarged end bushings 3'2, 34. An axial hole 46 (FIG.2) is formed in each bushing for receiving a reduced end portion 48 ateach end of the pivot shaft 24 whereby the same is supported forrotation within the bushings 32, 34 which are removably secured to thebase plate 10 by suitable fasteners such as the machine screw shown at50. By virtue of the above described structure, manufacture and assemblyis significantly facilitated since close tolerances are readily held onbushings 32, 34 to ensure dimensional integrity and their enlarged sizeeffects greater purchase for the screws 50 and increased strength ofassembly.

In addition, the disclosed pivot arrangement is particularly suited tomaintain the top plate 12 essentially free of lateral displacementduring a work forming operation. Each end bushing 32, 34 preferablyincludes a pair of annular flat springs or wave Washers 52 seatedagainst a shoulder 54 formed by an enlarged recess 56 at the outer endof each bushing 32, 34. The springs 52 are bottomed against the shoulder54 and compressed by means of a retaining ring 58 firmly seated by ascrew 60 threadably secured to the reduced end portion 48 of the pivotshaft 24. Upon adjustment of the screws 60 at opposite ends of the pivotshaft 24, oppositely directed axial spring forces are applied to thepivot shaft 24 whereby it is continuously balance-d under spring tensionand maintained against axial displacement while yet allowing for thenecessary movement between plates 10 and 12.

In this regard, it will be noted that if the plates 10 and 12 aredisassembled for any reason, the top plate 12 may be readily reassembledin proper working condition in a minimum period of time requiring only aminimal degree of skill.

The pivot shaft 24 is thus quickly and accurately located and assembledfor swinging movement of the top plate 12 toward and away from the baseplate 10, and the top plate 12 may be angularly adjusted relative to thebase plate 10 by positive contact between the front roll 22 and a gageblock such as that illustrated at 21 positioned on the base plate 10.The size of the gage block is selected for whatever dimension isrequired to locate a workpiece at a desired angle on the top plate 12as, e.g., in drilling, milling, surface grinding and similar workforming operations.

To set sines of small angles, the front roll 22 is shown as havingopposite end portions 62, 64 of reduced diameter. The reduction indiameter of the front roll 22 is preferably exactly 0.400 inch toprovide a 0.200 inch step on the front roll 22. The sine plate assemblyof the invention is thus adapted for use with standard sets of gageblocks conventionally available in heights above 0.100 inch, typicallyat successive increments of 0.0001 inch in gage block height.

In the course of various machining operations, my tendency of the topplate 12 to be lifted from the gage block assembly is minimized by meansof an improved clamp 66 provided in accordance with still anotherfeature of the invention. Clamp 66 generally comprises a rigid,adjustable length fastener 68 having opposite end portions connected toupper and lower toggle yokes 70, 72 respectively having rearwardlyprojecting shank portions 74, 76 removably insertable into sockets 78,80 formed in front ends 28, 82 of plates 12 and 10. The upper and lowertoggle yokes 70, 72 respectively include a pivot pin 84, 86 rotatablysupported between opposite legs of a generally U-shaped bracket portion88, 90 attached at forward ends of their respective shank portions 74,76.

In the preferred embodiment, fastener 68 is comprised of two separableparts including an internally threaded sleeve 92 fixed to pivot pin 86of the lower toggle yoke 72, and a bolt 94 slidably rceived in anaperture of pivot pin 84 of the upper toggle yoke 70 for pivotalmovement relative to the top plate 12.

In operation, shank portions 74, 76 of the clamp 66 are simply insertedinto the sockets 78, 80, and the lower threaded end of the bolt 94 issecured in the sleeve 92 after the angular setting of plate 12 isproperly adjusted relative to base plate 10. Bolt 94 is provided with anenlarged head 96, preferably slotted for receiving a setting instrumentsuch as a screwdriver, not shown, whereupon the clamp 66 is readilytightened to draw the head 96 of the bolt 94 into engagement with pivotpin 84 of the upper toggle yoke, thereby to lock top plate 12 inposition to provide the desired pressure on the gage block 21.

It is to be noted that a considerable mechanical ad vantage is providedby the described clamping arrangement wherein the holding force isapplied on the front ends of the plates 10, 12 to more effectivelyresist any tendency of the front plate 12 being lifted away from thebase plate 10. In addition, a set of bolts of varying length is providedto accommodate a full range of angular settings of the top plate 12, andthe overall length of the fastener 68 may be preselected accordinglysuch that it is continuously positioned within an included angle formedby a lower face 100 of the base member and the upper face of the topplate 12, thereby eliminating any possibility of the clamp 66interfering with a supporting surface for the assembly or with aworkpiece being supported on the top plate 12.

The sine plate assembly of the present invention is of durable compactconstruction providing ease and economy in its manufacture and assemblywhile yet maintaining the required dimensional integrity. The disclosedstructure also provides improved bearing support for the removable endbushings which as noted above are readily disassembled and reassembledby relatively unskilled labor to provide a proper pivotal connectionbetween the movable plates. In addition, the above described structureis particularly suited to be quickly and easily set to securely hold aworkpiece at a desired angle, even at small angles, without danger ofthe adjusted position of the assembly being disturbed during a machiningoperation. As will be ap parent to those skilled in the art, thefeatures disclosed in the preferred embodiment could be readilyincorporated in similar tools for obtaining compound angles.

As will be apparent to persons skilled in the art, various modificationsand adaptations of the structure above described will become readilyapparent without departure from the spirit and scope of the invention.

Iclaim:

1. A sine plate assembly comprising a base member and a top member eachhaving a socket formed in a front end thereof, said top member beingpivotally connected adjacent its rear end to said base member, and anadjustable removable clamp including upper and lower toggle yokes eachhaving a shank portion removably insorted into said sockets of said basemember and said top member respectively, and a rigid adjustable lengthfastener having opposite end portions pivotally connected to said toggleyokes for precluding movement of said top member from a preselectedangularly adjusted position with respect to said base member, saidfastener being extensible to permit quick release of said clamp fromsaid members.

2. The assembly of claim 1 wherein said clamp is continuously positionedwithin an included angle formed between a lower face of said base memberand an upper face of said top member irrespective of said angularlyadjusted position of said top member relative to said base member.

3. The assembly of claim 1 wherein said upper toggle yoke includes anapertured pivot pin, and wherein said adjustable length fastenercomprises an internally threaded sleeve pivotally connected to saidlower toggle yoke, and a bolt slidably received in said apertured pivotpin of said upper toggle yoke and threadably secured in said sleeve forselectively adjusting the length of said fastener, said bolt having ahead at one end thereof engageable with said apertured pivot pin forprecluding swinging movement of said top member away from said basememher.

4. A sine plate assembly comprisng a base plate and a top plate eachhaving an upper face including a flat finished surface and a lower face,said upper face of said base plate having a lateral recess extendinginwardly from opposite side edges thereof adjacent its rear end, a frontroll and a pivot shaft spaced apart in parallel relation and secured tosaid lower face of said top plate adjacent front and rear ends thereofrespectively, a pair of bushings coaxially mounted on said base plateand rotatably supporting said pivot shaft for swinging movement of saidtop plate toward and away from said base plate, said bushings eachhaving an outside diameter of enlarged size relative to that of saidpivot shaft and being positioned in said lateral recess of said baseplate whereby center lines of said front roll and said pivot shaft arereadily and precisely located in a common plane parallel to said flatfinished surfaces of said plates when said front roll is in engagementwith said base plate, said base plate and said top plate each having asocket formed in said front ends thereof, and an adjustable removableclamp comprising a rigid adjustable length fastener having opposite endportions and a pair of toggle yokes pivotally connected thereto, saidtoggle yokes each having a shank portion removably inserted into saidfront end sockets of said base plate and said top plate for precludingmovement of said top plate from a preselected angularly adjustedposition with respect to said base plate, said fastener being extensibleto permit quick release of said clamp from said plates.

5. A sine plate assembly comprising a base member and a top member eachhaving a socket formed in a front end thereof, said top member beingpivotally connected adjacent its rear end to said base member, and anadjustable removable clamp including upper and lower toggle yokes eachhaving a shank portion removably in- -serted into said socket of saidbase member and said top member, respectively, each also having agenerally U- shaped bracket portion connected to each said shankportion, a rigid adjustable length fastener having opposite endportions, respectively, pivotally connected to said U-shaped bracketportions for precluding movement of said top member from a preselectedangularly adjusted position with respect to said base member, saidfastener being extensible to permit quick release of said clamp fromsaid members, and a pivot pin mounted between opposite legs of each saidU-shaped bracket portion providing the pivot connection between saidopposite end portions of said fastener and said toggle yokes.

References Cited UNITED STATES PATENTS 2,733,702 2/1956 Barrett.2,442,136 5/1948 Luther. 2,190,455 2/ 1940 McCollum et a1 210632,351,773 1/1944 Lovenston.

646,499 4/1900 Lodge.

10 LEONARD FORMAN, Primary Examiner.

S. STEPHAN, Assistant Examiner.

